fentanyl at a glance
Medicine class
Strong opioid analgesic
Important safety point
Remove the old patch before applying another, and never cut a patch.
Heat warning
External heat can increase fentanyl absorption and overdose risk.
What is fentanyl used for?
The selected patches are licensed for continuous opioid treatment of severe chronic pain.
Adults with severe chronic pain requiring continuous opioid administration.
Opioid-tolerant children aged 2 years and over with severe chronic pain.
How does fentanyl work?
Fentanyl activates opioid receptors in the brain and spinal cord, reducing pain transmission and perception. Patches release fentanyl through the skin into the circulation. Effects can persist after removal because fentanyl remains in the skin and leaves the body gradually.
fentanyl preparations and strengths
Transdermal patch
Route: Transdermal
Strengths: 12 micrograms, 12 micrograms/hour, 25 micrograms, 25 micrograms/hour, 37.5 micrograms/hour, 50 micrograms, 50 micrograms/hour, 75 micrograms, 75 micrograms/hour, 100 micrograms, 100 micrograms/hour
How to take fentanyl
Follow the supplied leaflet and prescriber's instructions carefully.
Apply to clean, completely dry, non-irritated and non-irradiated skin on a flat area of the torso or upper arm.
Clip hair if needed; do not shave the site or use soap, oils, creams, lotions or powder there.
Do not cut, divide or use a damaged patch. Avoid touching its adhesive surface.
Press the whole patch firmly into place, check the edges adhere and wash your hands with water afterward.
Remove the previous patch before applying another and use a different skin site.
Keep patches away from heating pads, electric blankets, hot-water bottles, saunas, prolonged hot baths and intense sunlight.
Fold used patches adhesive-side inward and keep them secure until disposal as instructed by a pharmacist.
fentanyl side effects
Common or expected effects
- Constipation
- Nausea or vomiting
- Sleepiness
- Dizziness or headache
- Itching, sweating or skin redness
- Dry mouth
- Tiredness
Get urgent medical advice
- Slow, shallow or difficult breathing, extreme sleepiness or loss of consciousness
- Severe allergic reaction, including swelling or breathing difficulty
- Agitation, fever, sweating, diarrhoea, muscle rigidity or overactive reflexes suggesting serotonin syndrome
- Severe abdominal swelling, pain or vomiting with inability to pass stool or wind
- Seizure or marked reduction in consciousness
fentanyl in pregnancy
Fentanyl may occasionally be considered when severe pain during pregnancy requires treatment, but the benefits and risks need specialist or prescriber review. Regular use, particularly later in pregnancy, may cause withdrawal or breathing problems in the newborn. The selected patches are not recommended during childbirth.
fentanyl while breastfeeding
Seek product-specific advice before breastfeeding. The selected patch product information advises against breastfeeding during treatment and for a period after patch removal because fentanyl enters milk and may sedate or suppress breathing in an infant. Specialist guidance describes cautious use of some fentanyl formulations with infant monitoring, so formulation and clinical circumstances matter.
fentanyl interactions
Check all prescribed, over-the-counter and recreational substances because interactions can cause sedation, breathing problems, withdrawal or altered pain control.
Benzodiazepines, sedatives, other opioids and anaesthetics
Combined central nervous system depression can cause profound sleepiness, low blood pressure, respiratory depression, coma or death.
Gabapentin or pregabalin
The combination increases sedation and respiratory-depression risk and requires careful clinical review.
Common questions about fentanyl
Answers are fully visible for fast scanning and source review.
Can fentanyl patches be cut?
No. Do not cut, divide or use a damaged patch because delivery may become unsafe or unreliable.
What if a patch sticks to someone else?
Remove it immediately and seek urgent advice. Call 999 if the person becomes unusually sleepy or has breathing difficulty.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.